Slice onions lengthwise, then boil in salted water until tender.,Drain and set aside.,(If you're going to use it as a topping, roughly chop the onions instead of slicing them lengthwise.),In the top of a double boiler over water, melt butter and blend in flour and salt.,Add milk, stirring until thick and bubbly.,Add minced garlic and cheese and cook, stirring, until cheese is melted.,Add cooked onions and heat.,Add salt and pepper, to taste.,______